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Questions tagged [inverse]

In mathematics, a function y=f(x) tells us how to map input x to output y. Inverting a function (or an operator) is attempting to find a function f¯¹ that maps y to x, such that x=f¯¹(f(x)).

In mathematics, a function y = f(x) tells us how to map input x to output y. Inverting a function (or an operator) is attempting to find a function f -1 that maps y to x, such that x = f -1( f(x) ).

It is not always possible to find the inverse map, and sometimes it does not even exist.

One of the most common inverse problems is inverting an n × n matrix: only square matrices A with det(A) ≠ 0 have an inverse matrix A-1. See .

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Divide windows form into 4 section and view diffrent orientation panel in each section

I want to develop the windows desktop application(.NET) for the large all in one touch screen. the screen must be divided into 4 section and lower sections view as normally and upper section view as flipped(reversed). because we have 2 user that…
vahid kazemi
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Large Sparse Symmetric Inverse

Nowadays, I'm writing a paper about graph processing. In experiments on my paper, I wanna write a scalability issue of my algorithm. the performance of algorithm depends on the inverse operation. the performance of Matlab inv function is really…
kujungmul
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my Modulo Inverse in clojure Seems to give wrong answer

Hi I am programming in clojure and though the problem of modulo inverse has nothing to do with language i am stuck at this code - (defn EulerDiv [x p] (let [ToMod (+ p 2)] (loop [num 1 toPow (int p) numDouble x] (if (= 0 toPow) …
Ashish Negi
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Inverting ill-conditioned matrix in NumPy

I am trying to invert a covariance matrix to calculate a Mahalanobis-distance. However, my covariance matrix is very ill-conditioned (condition number > 10^17). This apparently leads to large rounding errors, resulting in a "matrix inverse" that…
der_herr_g
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C# implement function about way synchronization

I did this: businessCRM.Description = string.Format("{0}\n" + "Name: {1}\n" + "Street: {2}\n " + "Number: {3}\n" + "floor: {4}\n" + business.Name, business.Address.Street, …
user1911
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Returning the inverse matrix from a cached object in R checking that input matrix has not changed

Disclosure: This is from a programming assignment from a Coursera Course called R programming. I originally had up the full code but took parts of it out since I realize I am not permitted to upload my full code (granted the code I uploaded didn't…
buehlerdm
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Get inverse list of files through dir command in batch

I'm triying to get a list of files of subfolders in a inverse order using this: for /f "tokens=*" %%f in ('dir /s /b /o-n') do (echo %%f) I'm getting this result folder1\file2, folder1\file, folder2\file2, folder2\file1, folder3\file2,…
alesinho
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NHibernate many-to-many inserts null id with hilo generator

I have 3 tables: User, Department and UserDepartment. User can be associated with multiple departments and department can be associated with multiple users. I use many-to-many fluent mapping on both sides like this: For Department HasManyToMany(x =>…
vsevolod
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I used least square method but matlab return compeletly wrong answer

I must solve an over constrained problem (Equations more than unknowns). So I have to use least square method. First I create coefficient matrix .It is a 225*375 matrix. For inversing, I use pinv() function and then multiply it in load matrix . My…
mohsen
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Matrix Inverse algorithm doesnt work inside my Code

My group and I are trying to create a bridge simulation. For that we need to calculate the inverse of a big matrix. So we got an open source algorithm which after testing it with this site:…
Lamaun
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c like string inverse not working for input c like string with less than 5 chars

Here is the function: void reverse(char* str) { char * endOfString = str ; char temp ; if(str) { while(*endOfString) { ++endOfString; } --endOfString ; while(str <…
Nikos
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Perl: Split string by everything but whitespaces

I want to split a string by everything but whitespaces. Example: Assume that I have a string: "The quick brown fox jumps over the lazy dog" I want to split it and get the following list of space-strings: [" ", " ", " ", " ", " ", "…
SomethingSomething
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Lowpass then Inverse Filter in Python

Trying to write a simple lowpass filter in python to run against lena. Then I'd like to run an inverse filter to run against the lowpass and try to get the original back (well, as close to original). I'm new to programming in python and not quite…
user3433572
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inverse of a large block diagonal sparse matrix in r

I would like to compute the inverse of some large block diagonal sparse matrix. The number of rows and columns is somewhat over 50,000. The blocks are 12 by 12 and are sparse (27 non zero elements). I tried to compute the inverse of the entire…
user3499209
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Inverse-square law equation

I have a light sensor which reads light intensity from 0 to 4095. I struggling to to write an equation using the inverse-square law of light so that when the light is lowest (let's say lowest ambient light is 50), it returns 1, and if highest…
ajq88
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